MAJOR PROBLEM WITH HP COMPUTER?

A little while ago I signed onto my account and before it let me into it a little box came up and said something about how my settings weren't all in place- i'm not sure because i ignored it. But I signed on and all of my stuff was deleted and all my programs were uninstalled and my background picture was gone. I noticed the keyboard was on 'Num Lock', i don't know if that has anything to do with it. But I went back on my account a little later and everything was back, then it happened again, everything deleted and everything's been deleted since. WHAT HAPPENED?!